Generally speaking, while a data sending terminal transmits a data to a data receiving terminal, the transmission rate of these terminals has better to be the same for making sure the success of transmission. The universal asynchronous receiver transmitter, abbreviated UART, is the most common transmission interface used in the embedded system, the unit of the transmission rate defined in the protocol of the UART is represented by the baud rate which means the bits transmitted per second. The common used baud rate of the asynchronous receiver transmitter comprises 1200, 2400, 4800, 9600 and 19200, etc. For correct transmission, the transmission between the data sending terminal and the data receiving terminal should be in the same baud rate. The transmission rate is usually generated by dividing a reference frequency by a divisor. There are different divisors corresponding to different transmission rates respectively.
However, the difference of mathematical calculations for the above division by the respective manufacturers, such as rounding up or down of the division, often result in the inaccuracy of transmission rate. Therefore, even if the data transmitting apparatuses which come from different manufacturers are set the same baud rate, the differences of the actual transmission rates among the data transmitting apparatuses still exists, so the frame error often occurs during data transmission and it reduces the transmission efficiency. The problem mentioned above becomes more serious when the baud rate is set to be higher.
In view of the shortcomings of the prior art, the inventor of the present invention based on years of experience in the related industry to develop a data transmission rate adjustment system and its method to overcome the shortcomings of the prior art.